Spark gap device



Dec. 27, 1949 W. J. KNOCHEL sfARK GAP DEVICE Filed NOV. 20, 1947 INVENTOR BY I WWW

ATTORNEY Patented Dec. 27, 1949 SPARK GAP DEVICE William John Knochel, East Orange, N. J., as-

signor to Westinghouse Electric Corporation,

East Pittsburgh,'Pa., a corporation of Pennsyl- Vania Application November 20, 1947, Serial No. 787,145

3 Claims.

This invention relates to spark gap devices, and more particularly to devices of that character for use in connection with pulsing of electrical wave energy, and is an improvement upon showing of structures forming the subject matter of United States Patents 2,411,241, 2,422,324, and 2,427,086, all of which are assigned to the same assignee as the present invention.

The commercial devices constructed in accordance with the aforementioned patents have shown a tendency both in manufacture and in use to develop cracks in the glass or elsewhere, the cause of which seems to be due to unequal expansion of parts of different materials. The present invention is directed primarily to overcoming the defect in the prior art construction and to improve thereover by providing a spark gap device capable of withstanding, without in-= jury, very considerable differences of temperature from below freezing encountered in use to or above metal-brazing and glass-sealing temperatures encountered during fabrication. The invention further contemplates accomplishment of its primary purpose without adding to the external dimensions of the device and without alteration of the electrical characteristics and electrode sizes or spacings, and at the same time obtain rigidity in the assembly and simplicity'of boththe means and methods of fabrication.

Other objects of the invention will appear to those skilled in the art to which it appertains, as the description proceeds, both by direct reference thereto and by implication from the context.

Referring to the accompanying drawing in which like numerals of reference indicate similar parts throughout the several views;

Figure 1 is a longitudinal sectional view of a spark gap device constructed in accordance with the present invention; I

Figure 2 is a cross-section of line II--II of Figure 1;

Figure 3 is a perspective view of a uniting collar constituting an essential part of the present invention; and

Figure 4 is a fragmentary longitudinal sectional view showing the collar in process of being welded in place.

In the specific embodiment of the invention illustrated in said drawing, the device selected for examplification herewith comprises a vitreous or glass cylindrical envelope Ill closed at each end by cup-shaped caps or heads II and 12 the rims whereof are sealed to the end margins of the glass cylinder. Preferably the caps or heads are of a metal or allow having the same or substantially the same coeflicient of expansion as the.

within the cylindrical envelope by being welded at one end to one of said caps or heads, H, in the same manner as carried out in prior art practice. The other cap or head l2 provides a flat shoulder M of washer-like shape the outer periphery of which is spun or bent at right angles to the plane thereof to provide rim E5 to which the glass cylinder is sealed. The inner periphery of said washer-like shoulder also bends or is spun to project at right angles to said shoulder but in a direction opposite to that of the outer peripheral rim, and thereby provides a hollow neck [6 projecting axially outwardly of the envelope. This neck l6 has an annular member I! welded or otherwise sealed therein for making the envelope vacuum tight, and this member I may conveniently provide an exhaust tubulation I8, through which the envelope is exhausted and then recharged with the desired ionizable medium, such as a mixture of about hydrogen and 20% argon at about 680 mm. pressure.

Within the envelope, coaxial with the glass cylinder, and coaxial to and spaced from the anode I3 is a metallic cylinder constituting another electrode or cathode l9, said cathode preferably being aluminum, and projecting longitudinally inward from the said cap having the shoulder l4 and neck l6 above described, said neck and cathode being approximately of equal diameter but extending in opposite directions from the said shoulder.

Intervening between the cathode and shoulder is a supporting and attaching collar 20, detail showing of which appears in Figure 3. Said collar provides a tubular portion 2|, at one end of which is a radially outwardly directed flange 22. At intervals circumferentially, the flange is split radially at 23 with the splits continuing part way of the length of the tubular portion, thereby providing tongues 24 integral with the tubular portion following the contour thereof as well as being in part in the same plane as the flange. The planar parts of the tongues furthermore are stamped or otherwise provided with ribs or projections 25 on what may be termed their under faces. Inasmuch as the tubular portion of the collar 20 has approximately the same diameter as the neck I 6 of cap i2, said flange and its tongues may be juxtaposed upon shoulder 44 with the collar coaxial to the cap. In the assembly of collar and cap, shoulder i 4 is carried upon a lower welding die 26, see Figure 4, and the collar flange is situated on said shoulder and an upper-"die 21 forcibly pressed downward to-. ward the lower die with simultaneous application of the welding current. By virtue of said pro- =1 jections and simultaneous pressure and welding current, the said tongues rare flattened: and Welded to the shoulder and the entire flange brought into engaging support. against11the shoulder. The cathode cylinder isapplied over the tubular partion of the collar andwelded thereto either before or after, but preferably before, welding of the collar to the'cap' shoulder;

By reference, said collar is of iron the. coefficient of expansion of; which is close enough to that of the aluminumicathode to assureconstant' bond thereb'etween especially. in view' of" the annular portion of the collar and juxtaposed portion of thecathodebe'ing thin at'the lapping, regionsthereof. Radial expansion'of the shoulderandi'differencein' expansion of" the cathode and glass'cylinder is accommodated by the flexibility of the several tongues 24. Furthermore, since the. iron comprising collar Zlihas a coefiicient. of

expansion intermediate between coeificients of closure, a metallic cap at the other end of'said' envelope sealedthereto, a second electrode'coaxial to'the first'said-electrode and envelope and extendinginwardly of said envelope from said. caphand an intervening member between said cap-and second electrode-and attached to both and supporting said second electrode from said cap, said member having a flexible portion between attachment of said member to the second electrode and to the cap.

2. A spark gap device comprising a cylindrical envelope having a closure at one end and an electrode supported thereby and said electrode extendingg'axially withinzsaid envelope from the closure, a metallic cap at the other end of said envelope sealed thereto, a second electrode coaxial to the first said electrode and envelope and extendin'gzinwardly of said envelope from said cap, and an interveningamember between said cap anjdi secondi'electrode and attached to both and 's'upporting said-second electrode from said cap,

said member having tongues integral therewith and secured to the said cap for constituting the attachment"of"said" intervening member to the cap '3'. A spark ap devicezcomprising a cylindrical envelope having a closure at one enduandl an electrode supported. thereby and said electrode. extending axially w'ithin saidenvelope from the. closure; a metallic cap atv the other end of said' envelope sealed thereto; a'second electrode coaxial.

to the firsts'aid electrode andenvelope and ex:

tendinginwardly of said. envelope from saidcap,

and an interveningmember between said cap and second electrode" and attached'to both and supporting said second electrode from said cap,

said" member comprisinga collar having a tubular portion'secured to said secondpelectrode and'having aflange next said cap; tongues secured to said i cap:

WILLIAM JOHN KNOCHEL.

REFERENCES CITED The. following, references are. of: recordin the fileof. this patent.

UNITED STATES PATENTS Number Name. Date.

2,367,331 Bondley, Jan. 16,1945. 2,422,324 WTatr0i1s June 1.7, 19.47. 2,427,086 Arnott etlal .Sept..9., 19.41 2,440,153 Oles. Apr-..20,.1948l said". flange having. 

